BMR Calculator
Your BMR is the number of calories your body burns at complete rest just to keep you alive. Enter your age, sex, height, and weight in metric (cm, kg) or imperial (in, lb) units to get your estimate.
BMR & calorie needs
Estimate your Basal Metabolic Rate — calories burned at rest.
FAQs
What is the difference between BMR and TDEE?
BMR is the calories you burn at total rest. TDEE (total daily energy expenditure) adds everything else — walking, working, exercise, even digesting food. Multiply BMR by an activity factor (roughly 1.2 to 1.9) to estimate TDEE.
Does BMR change with age?
Yes, it slowly declines with age, mainly because muscle mass tends to decrease. The Mifflin-St Jeor equation subtracts 5 calories per year of age, so strength training that preserves muscle is the main way to slow the decline.
How it works
BMR is estimated with the Mifflin-St Jeor equation. For men: 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5. For women the last term is −161 instead of +5. A 30-year-old woman who is 165 cm and 65 kg gets 10×65 + 6.25×165 − 5×30 − 161 = 1,370 calories per day.
Prefer imperial? Convert first or enter directly: a 30-year-old man at 5'10" (178 cm) and 180 lb (82 kg) has a BMR of about 1,793 calories per day. The calculator handles either unit system.
BMR covers only resting energy — breathing, circulation, and cell maintenance. To estimate total daily burn, multiply BMR by an activity factor (about 1.2 for sedentary, up to 1.9 for very active). Use the result as a starting point for meal planning or weight goals, not a precise prescription.
Your body burns most calories doing nothing
For most people, BMR accounts for roughly 60–75% of all calories burned in a day. Keeping your heart beating, lungs breathing, and brain running is genuinely expensive in energy terms.
That is why crash diets backfire: cutting far below BMR signals the body to conserve energy, making further loss harder and rebound likelier.
Muscle is the biggest lever you control
Muscle tissue burns more calories at rest than fat tissue does. Two people with the same weight can have BMRs hundreds of calories apart depending on body composition.
This is the real reason strength training helps with weight management — it raises the floor of what you burn all day, every day, not just during the workout.
Using your BMR number wisely
Multiply your BMR by an honest activity factor to estimate daily needs, then adjust food intake in small steps — 200 to 300 calories at a time — and watch the trend over two to three weeks.
If the scale is not moving, recheck portion sizes before cutting further. Going below BMR for long stretches is rarely sustainable and often counterproductive.